Dbaft gear



L. M. CLARK DRAFT GEAR Dec. 19, 1933.

Filed March l2, 1932 Patented Dec. 19, 1933 PATENT oFF-ICE nam GEAR Leverett M. Clark, Depew, N. Y., assignor to Waugh Equipment Company, Depew, N. Y., a

corporation of Maine Application March y12, 1932. Serial No. 598,348

8 Claims. (Cl. 213-32) This invention relates to a draft gear'.

Heretofore draft gears or friction mechanism have not been provided with any definite means for equalizing the actuating pressures over ther entire contacting surfaces of the` friction generating members'. The equalia'ation of such actuating pressures is exceedingly important for the reason that the same any undue abrasion and the resultant wear of the surfaces and in promoting uniform and smooth action of the energy-translating operation Vas well asin furthering and insuring a positive release Vor return of the operating parts after applied pressures have been removed.

In addition to the means for equalizing the actuating pressures as abovereferred to, it is also important that the most uniform action be obtained'between the actuating and friction generating members in order to make it possible to employ any ordinary combination of contacting members. One way of obtaining this resultinvolves the coating of one or both of the actuating pressure surfaces with lead or lead alloy to permanently reduce and stabilize the coefficient of friction of these surfaces, eliminating all undue abrasion and` wear so as to more uniformly control the applied pressures against the friction-generating surfaces. `In view of the fact that the differentiated movements between the actuating and friction-generating members are very smallQlead or lead alloy inserts in one or Aboth of the surfaces would not properly function to produce the result` occurring bythe use of a lead or lead alloy coating. Y

Another feature of this invention `resides -in a structure wherein the tie-bolt is combined with the equalizing member that makes the assembly self-contained and for holding it to a definite length. f

The invention comprises the novel structures and combination of parts hereinafter described and more particularly pointed out and defined in the appended claims.

In the accompanying drawing which illustrates certain preferred forms of this invention and in which similar reference numerals refer to similar features in the different views:

Figure 1 is a longitudinal sectional view through a draft gear involving this invention.

Figure 2 is a view similar to Figure 1 showing the parts in a different position.

Figure 3 is a reduced sectional view taken upon the line III- III of Figure 1 looking in the direction of the arrows.

Figure 4 is va, slightly reduced `sectional `view A form the friction-generating member. side wedges are preferably provided with a coattaken upon the line IV-IV of Figure flocking in the direction'of the arrows.

trating a slight modification of the invention.

Figure 6 is a sectional view taken substantially in the same plane as Figure 3 but illustrating a slight modification of certain parts of this invention.

As illustrative of this invention, there is shown in the drawing especially in Figures 1 to 4, a rectangular casing 1, a pair of side-wedges 2 which coact with the surfaces of the casingV to These ing of lead or lead alloy 3 upon their outer surfaces. Between the side wedges 2 there are a pair of center wedges 4 which coact with the inclined surfaces of the side wedges 2.. The inclined surfaces of the central wedges 4 are coated with lead or lead alloy 5 or the like. Whenever an external force or pressure is appliedto the outer extended end of the center wedges 4, ithe side wedges 2 are forced inwardly andY against the side walls of the casing 1 through the bridging resistance of the equalizing pin or member 6, which is positioned between the center wedges. It will be noted that the equalizing pin 6 is of substantially cylindrical form and occupies a concave recess in each central wedge 4 and equalizes the actuating pressures over the entire contacting surfaces of the friction generating members. A tie-bolt 7 integral with the equalizing pin or head 6 extends longitudinally through the casing 1 and is slidably mounted in the inner Vwall 8 of an inwardly extending hollow boss 9 integral with the casing and extending inwardly from the inner end thereof. V'Ihe nut l() upon the inner end of the tie-bolt '7 is adapted for engaging the Vwall 8 for limiting the outwardv movement of the wedge elements 2 and4.

A relatively stout coil spring 11 in the casing bears against the inner edges of the side `wedges 2 and a lighter coil spring 12 is in the 'large coil spring 11 and positioned upon the boss 9 and bears against a follower 13, which in turn bears against laterally offset heads 4a on the central wedges 4 and which laterally offset heads 4a are located in suitable recesses in the inner ends of the side Wedges 2. It will be noted that the engaging surfaces of theheads 4a and the follower 13 are suitably beveled or inclined in order that, whenever externally-applied pressures have been removed from the outwardly-projecting ends of center `Wedges 4, the pressure of helical spring 12 can imbalance the center wedge pressure groups. .wedges and the side wedges will tend to reduce against the adjacent side wedges suiciently to cause the combined pressures ci sL rings 11 and 12 to return the wedges to normal position.

It will be appreciated that by the employment of the hollow boss 9 at the end cf the casing, the rod 7 is supported at a point within the casing and need not be extended beyond the casing.

In Figure 5, there is shown a slight modification which differs from the foregoing structure in that the equalizing pin 6a does not extend entirely across the casing as shown in Figure 4.

In this modified form of structure, the equalizing pin 6a is shorter than the width of the central wedges 4, the opposed faces. of whichv are provided with arcuate recesses for receiving the said equalizingv pin.

In Figure 6, there is shown a slightly modified form of structure in which the casing 1a is of octagonal form. It will be noted that in this form of the invention, the side wedges 2a are provided with inclined lateral lips 2b that engage beveled corners on the central wedges 4b. vIt will be obvious that in this modiiied form of construction, therecan be no lateral play between the side wedges 2a and the central lwedges 4b.

Whenever an external force or pressure is applied to the outer extended ends of the center Wedges 4, the side wedges 2 are forced against the casing through the bridging resistance of the equalizing pin or member 6. As soon as the static resistance of the side wedges 2 has been overcome, the center and side wedges are moved into the casing 1 against'the resistance of the pre-compressed helical springs l1 and 12 until the combined frictional and spring resistance equals the externally applied pressure.

center wedges away from the side wedges 2 with the equalizing pin 6 acting as a fulcrum, but the greater pressure which-is externally applied to the center wedges 4 counteracts this tendency during the inward movement of the wedge The lead coating' between the central the coefficient of friction while the lead coating between the side wedges and the housing will tend to stabilize the coeflicient'of friction.

It will be considered that various forces or pressures of variousvmagnitudes will be'applied externally to the outwardlyA projecting ends of the center wedges 4 according to the operation of railway vehicles, colliding jspeed, rates of speed changes between adjacent vehicles, pulling forces of locomotives, etc., and that the corresponding movements of the wedge groups and the amount of kinetic energy-translation will be governed thereby up to the limit of wedge group travel or the cushioning capacity of the friction mechanism. When previously applied forces or pressuresare removed from the outwardly projecting ends of center wedges 4, the pressure of helical spring 12 acting through follower 4a against angular surfaces of center wedges 4 unbalances the center wedge pressure against adjacent side wedges sufficiently to cause the combined pressures of springs l1 and 12 to return the wedges to normal position. It is to be noted that the partially compressed spring il. when the mechanism is released as described, forces the side wedges 2 against the center are operating on curved tracks.

vsaid Wedges.

are normal thereto but also when such forces yor v pressures are applied at an angle to the center wedges as occurs when railway vehicles It will therefore be apparent, that the capacity and operating characteristics of the friction mechanism will not be materially affected when external forces or pressures are applied at an angle to theA center wedges.

I am aware that many changes may be made and numerous details of construction may be varied through a wide range without departing from the principles of this invention, and I therefore do not purpose limiting the patent granted hereon otherwise than necessitated by *the prior art.

I claim as my invention:

1. In a friction mechanism of the class described, a housing, a pair of side wedges slidably mounted in said housing, a pair yof center wedges between said side wedges, an equalizing memberpbetween said center wedges, a rod integral with said equalizing member, means for equalizing member tending to spread said center wedges against saidrside wedges, said vcenter wedges having inner beveled ends, a follower cooperating with said beveled ends, and yielding means pressing against said follower tending to withdraw said center wedges from contacting relation with said side wedges.

2. In a friction mechanism of the class described, a housing having an inwardly directed hollow boss at one end, a pair of side friction wedges within the other end of said housing, ya pair of center wedges between said side wedges, an equalizing member between said center wedges, said equalizing member having a rod slidably mounted in said boss, said side wedges having a recess and said center wedges having laterally extending heads lpositioned in said recess, a follower engaging said heads, said heads and follower having coacting inclined surfaces tending to draw the center wedges together, a spring within said housing bearing upon said Yside wedges, and a second spring within said supporting said rod Within said housing, said iio 3. In a draft gear, a housing, side wedgesn outer edges, a follower having beveled portions engaging the beveled portionsof said heads, la spring in said housing acting upon said follower and a second spring in said housing acting upon lindrical member mounted between said center wedges, said cylindrical member having a rod extending through said bearing wall and yielding means in said housing acting upon said center Wedges and said side Wedges.

5. In a draft gear, a housing, side wedges extending into one end of said housing, center wedges between said side wedges, said center wedges having their inner ends beveled upon the outer edges thereof, a follower having beveled portions engaging the bevels on said ends, a spring in said housing acting upon said follower and yielding means acting upon the inner ends of said side wedges.

6. In a draft gear, a housing, side wedges in said housing, center wedges between said side wedges, an equalizing member between said center wedges, said member having a rod extending longitudinally of said housing, means for slidably anchoring said rod for limiting the outward movement of said center` wedges and yielding means in said housing in opposed relation to said side wedges and center wedges.

'7. In a draft gear, a housing having an inward-Y ly directed boss at one end, a pair of side friction wedges within the other end of said housing, said Wedges having a coating of lead adjacent said housing, center wedges between said side wedges, an equalizing member between said center wedges having a rod slidably mounted in said boss, said center wedges having a coating of lead contacting said side Wedges and yielding means acting on said wedges.

8. In a draft gear, a housing, side wedges extending into one end of said housing and having a coating of lead adjacent said housing, center wedges between said side wedges and having a coating of lead adjacent said side wedges, the inner ends of said center wedges having their outer corners beveled, a follower having beveled portions coacting with said beveled corners for drawing said center wedges together, yielding means acting upon said follower and yielding means acting upon the inner ends of said side wedges.

LEVERETI M. CLARK. 

